It is known that the greatest limitation in the use of conventional bicycles consists in that the conventional bicycle activates only the muscles of the legs, while the arms direct, stabilize, and brake the bicycle, without performing any pulling force.
For solving the above mentioned disadvantage, the prior art describes many systems for applying force to move bicycles, including systems that combine the action of the legs and the pelvis or even of the legs and the arms.
All of the known systems, however, are disadvantageous to use because they reduce the user's ability to balance the bicycle, and/or reduce the user's ability to maneuver the bicycle, and/or make use of very complicated, expensive, and heavy mechanisms.
In U.S. Pat. No. 632,797, granted on Sep. 12, 1899 to G. VAN HORN, a bicycle is described with a handle-bar having the form of cranks, which is used for applying a pulling force with the arms. This handle-bar crank system includes a connection with the back wheel of the bicycle. This rotating handle-bar rotates a toothed wheel, which in turn is connected, by means of a very long chain, to another sprocket wheel provided near the conventional sprocket wheel operated by the foot pedals.
The disadvantage of the bicycle described in this patent consists in that the extremely long, continuous chain--from the handle-bar to the pedal-hub, is twisted when the handle-bar is turned for directing the bicycle.
Many years later, this problem was faced in Canadian Patent No. 606,713 of Ernesto Nacar, who, starting from the bicycle of G. VAN HORN, tried to prevent the twisting of the chain that connects the rotating handle-bar to the pinion of the pedals that moves the rear wheel. The device described in this patent includes a considerable series of gears connected to transmission shafts and chains, which seemed to allow the adhesion of the chain even when the handle-bar was turned. The mechanism is very complex and presumably very heavy.
The application of a pulling force, with direct connection to the front wheel of the bicycle instead of to the back wheel, is shown in Italian Pat. Application No. 48237 A/86 in the name of Roberto MEZZINI. In this device, a fork made integral with the central tube that usually supports the handle-bar is directed with prongs upward and is provided, at the upper end, with a pedal keyboard placed in such a way as to be operated by the hands of the cyclist. The system is connected, by means of a chain, to the hub of the front wheel, which is provided with a pinion.
The bicycle is provided with counter-pedal brakes inserted in the hub.
This kind of bicycle makes use of a movement equal to the one produced by the legs by using the same kind of pedals near the handle-bar.
The evident disadvantage of this device is the lack of stability and the difficulty in directing the bicycle, as the arms are to be held in positions never specular to each other, as occurs with a conventional handle-bar. The same inventor tried to solve this problem on his own, as shown in Patenta Application No. RM 95 A 000 608 of Sep. 12, 1995, in which, together with the pedal-keyboard, a second, fixed handle-bar and a second saddle are provided, mounted near the fixed handle-bar, and onto which the cyclist rests his breast for finding better balance while driving the double-traction bicycle.
Further double-traction bicycles have been described, which make use of levers or lever systems, e.g., by Antonio GOMEZ ZARCO in Spanish Patent Application No. 523,432 of Jun. 21, 1983, and by Horst EIFLER in German Patent No. DT 243677A1.
Thus, in the bicycle art, considerable effort has been made in creating an auxiliary traction mechanism in addition to that used for the back wheel, wherein the auxiliary traction mechanism makes use of the arms of the cyclist, which pull levers or rotate the handle-bar.
The results of these efforts have produced products having a considerable lack of stability and very complicated mechanisms.